An error propagation stochastic model is described and used to study the impact of both photon and photoresist material sources of line-width roughness (LWR). Based on typical chemically amplified resist parameters, material sources of LWR are shown to be of equal importance to photon sources. Of the material sources, quencher is shown to be the most important input noise term. The results show that it is not the relative quencher noise that ultimately matters but rather the absolute quencher noise relative to the mean produced acid count. The results also show that chemical yield is critical and that benefiting from increased absorptivity also requires the chemical yield to be maintained.

A contact-hole deprotection blur metric has been used to monitor the deprotection blur of an experimental open platform resist (EH27) as the wt % of base and photoacid generator (PAG) were varied. A six times increase in base wt % is shown to reduce the size of successfully patterned 1:1 line-space features from 52 to 39 nm without changing deprotection blur. Corresponding isolated line edge roughness is reduced from 6.9 to 4.1 nm. A two times increase in PAG wt % is shown to improve 1:1 line-space patterning from 47 to 40 nm without changing deprotection blur or isolated line edge roughness. A discussion of improved patterning performance as related to shot noise and deprotection blur concludes with a speculation that the spatial distribution of PAG molecules has been playing some role, perhaps a dominant one, in determining the uniformity of photogenerated acids in the resists that have been studied. © 2008 American Vacuum Society.